Abstract: A method of determining rate and phase of fluid produced from or injected into a hydrocarbon well includes obtaining first temperature and pressure measurements from sensors at the well. The first temperature and pressure measurements are applied to a plurality of predictive well models to calculate an estimated value of fluid rate and phase composition from each of the predictive well models responsive to the temperature and pressure measurements. A first fluid rate and phase composition result is derived from the estimate value of fluid rate and phase composition from each of the predictive well models.

Abstract: Physical models of wells are used to determine rate and phase composition for fluid produced from or injected into the wells on a near real time and continuous basis. The method can be used to alert operators or others of conditions in a well or field to permit more immediate response. The method can be more tolerant of sensor faults, sensor drift, anomalous data or other occurrences which could otherwise lead to incorrect output. More than one model can be used to permit a hierarchy of calculation such that the rate and phase determination is more tolerant of anomalous data. The calculated rate and phase values from one or more wells can be reconciled against facility data.

Abstract: The invention provides a stairlift chair in which the seat and armrests move simultaneously when the chair is folded. In a preferred embodiment the footrest also folds, with the armrests and seat, when the chair is folded.